Bulk-like phonon transport in multilayer graphene nanostructures with consecutive twist angles

Abstract

We investigate phonon transport in consecutively twisted multilayer graphene (CTMG) via atomistic simulations, assuming the same twist angle between any adjacent layers. Intriguingly, the calculated temperature drop between each two layers along the cross-plane direction in CTMG appears nearly identical, indicating an ill-defined Kapitza length. Moreover, the bulk-like thermal resistance increases with rising temperature. Both phenomena suggest that heat conduction in CTMG more closely resembles that in bulk materials as compared to layered materials with an individual mismatched interface, such as twisted multilayer graphene (TMG). This peculiar behavior originates from the unique nanostructure of CTMG. First, the common twist angle creates a consistent charge distribution at each interface, leading to a higher binding energy and reduced mismatch of the phonon density of states across the interface, and therefore a more uniform temperature drop. Further, the continuum of interfaces induces strong scattering of low-energy acoustic phonons generated by emission processes at the interfaces, which results in a temperature dependence opposite to that of TMG. Our findings enable a better understanding of phonon transport in twisted multilayer graphene, and may also facilitate the exploration of other interface-engineered van der Waals nanostructures.